Sustainable production of Lavandula stoechas carbon dots: Structural insights and targeted analytical performance for pesticide monitoring

Herein, we report the green fabrication of luminescent carbon quantum dots (CQDs) with intense ultraviolet (UV) emission through a facile solvothermal carbonization of Lavandula stoechas . The physicochemical and optical attributes of the as-prepared CQDs were systematically investigated via a suite of analytical techniques, including SEM, XRD, FTIR, XPS, and steady-state spectroscopy. Morphological assessments revealed quasi-spherical nanoparticles enriched with diverse hydrophilic functionalities, facilitating superior aqueous dispersibility and long-term photostability. Notably, XPS analysis corroborated the effective incorporation of nitrogen into carbonaceous architecture, indicative of heteroatom self-doping. The resulting nanomaterials displayed a robust fluorescence profile peaking at 345 nm, characterized by a substantial Stokes shift. Exploiting these unique photophysical features, a highly sensitive 'turn-off' fluorometric platform was engineered for the precise quantification of Chlorpyrifos. Following the optimization of experimental parameters, the sensing system yielded a broad linear dynamic range and a remarkable limit of detection (LOD) as low as 2.8 × 10 −8 M. Furthermore, the probe demonstrated exceptional selectivity against potential interferents, including diverse metal ions and organophosphorus analogs, with an ultra-fast response within 20 s. Practical feasibility was preliminarily evaluated using freshly spiked soil samples, yielding satisfactory recoveries of 101.1%–102.5% with good reproducibility. This work highlights the efficacy of Lavandula stoechas -based CQDs as a sustainable, cost-effective, and high-performance analytical tool for environmental surveillance.